fix clippy warning by latest nightly rust version (#319)

auction/src/default_weight.rs

@@ -2,6 +2,7 @@
 
 #![allow(unused_parens)]
 #![allow(unused_imports)]
+#![allow(clippy::unnecessary_cast)]
 
 use frame_support::weights::{constants::RocksDbWeight as DbWeight, Weight};
 

authority/src/default_weight.rs

@@ -2,6 +2,7 @@
 
 #![allow(unused_parens)]
 #![allow(unused_imports)]
+#![allow(clippy::unnecessary_cast)]
 
 use frame_support::weights::{constants::RocksDbWeight as DbWeight, Weight};
 

currencies/src/default_weight.rs

@@ -2,6 +2,7 @@
 
 #![allow(unused_parens)]
 #![allow(unused_imports)]
+#![allow(clippy::unnecessary_cast)]
 
 use frame_support::weights::{constants::RocksDbWeight as DbWeight, Weight};
 

gradually-update/src/default_weight.rs

@@ -2,6 +2,7 @@
 
 #![allow(unused_parens)]
 #![allow(unused_imports)]
+#![allow(clippy::unnecessary_cast)]
 
 use frame_support::weights::{constants::RocksDbWeight as DbWeight, Weight};
 

oracle/src/default_weight.rs

@@ -2,6 +2,7 @@
 
 #![allow(unused_parens)]
 #![allow(unused_imports)]
+#![allow(clippy::unnecessary_cast)]
 
 use frame_support::weights::{constants::RocksDbWeight as DbWeight, Weight};
 

rewards/src/default_weight.rs

@@ -2,6 +2,7 @@
 
 #![allow(unused_parens)]
 #![allow(unused_imports)]
+#![allow(clippy::unnecessary_cast)]
 
 use frame_support::weights::{constants::RocksDbWeight as DbWeight, Weight};
 

tokens/src/default_weight.rs

@@ -2,6 +2,7 @@
 
 #![allow(unused_parens)]
 #![allow(unused_imports)]
+#![allow(clippy::unnecessary_cast)]
 
 use frame_support::weights::{constants::RocksDbWeight as DbWeight, Weight};
 

vesting/src/default_weight.rs

@@ -2,6 +2,7 @@
 
 #![allow(unused_parens)]
 #![allow(unused_imports)]
+#![allow(clippy::unnecessary_cast)]
 
 use frame_support::weights::{constants::RocksDbWeight as DbWeight, Weight};